(i) Field of the Invention
This invention relates to improvements in means to secure cylindrical stems through apertures in the walls of conduits. This invention also provides the combination of the hollow stem and the conduit and a method for securing the hollow stem to the conduit. Although it is designed specifically for use for automatic sprinkler systems, nevertheless it will be appreciated that it can be used in other environments if necessary.
(ii) Description of the Prior Art
Normally, sprinkler system consist of underground conduits with sprinkler heads extending upwardly from the conduit at various locations. These sprinklers heads include a sprinkler tip assembly which is secured within the upper end of a cylindrical stem which in turn is normally screw threadably engageable to a lower cylindrical portion extending through the wall of the underground conduit. Conventionally, the portion of the stem extending from the wall of the conduit is secured through an aperture in the conduit by means of a saddle washer and external clamp assembly (as taught by Canadian Pat. No. 881,191 issued to Gerhard Dyck), because it is not possible normally to engage the conventional stems through the apertures from the inside of the conduit.
The external clamp and saddle washer assemblies described above are awkward and labour intensive to install. The clamps, being underground, and in a damp environment, often corrode unless they are made from a non-corrosive material, under which circumstances the cost is increased.